It is quite commonly found that some types of digital modules in a certain type of operating system will function to operate using, for example, a single word at a time, that is to say, the system is capable of reading one word or writing one word or processing one word in a unit time cycle of the particular system.
Likewise, there are other systems which operate on different type protocol operations such as, for example, systems which have digital modules which operate, for example, with the use of four word data bursts, that is to say, words are read in groups of four words or written in groups of four words or transferred in groups of four words.
The problem and difficulty arises when it is desired that digital modules of the first type of system (System A) are to be used in conjunction with digital modules of the second type of system (System B) in order to make them operate compatibly.
As a concrete example, the Unisys A16 system provides an architecture using a task control unit or TCU which communicates with other digital modules within its system using four word data bursts. Likewise, the input/output unit of the Unisys A16 system also has digital modules which communicate with four word messages.
Now when digital modules, such as the 4 word message protocol type, are desired to be integrated into a system where a different type processor is used, such as, for example, a processor which is able to read and write messages only one data word at a time, it presents numerous difficulties. In order to provide compatibility between a single word protocol processor, which in the example cited herein, could be designated as the IMP processor (Integrated Mainframe Processor) and a 4-word protocol digital system, certain accommodating translation mechanisms must be developed. This IMP processor has only the capability to read and write messages one data word at a time, but it was needful to develop a process to permit communication between the IMP processor and the previously known Unisys A16 digital modules designated as the Task Control Unit (TCU) and the Input/Output Unit (IOU) which required messages having four word quantities.
The present disclosure provides a translator means to permit four word request and acknowledgement messages to be exchanged between a Unisys IMP processor and other digital modules such as a Task Control Unit or an Input/Output Unit which are integrated into the processor's system, even though the word protocols are different and the clock rates of the digital modules are different.